Patches are spots of skin that are lighter or darker than your regular skin color. Patches may also have a red, purple, or blue tint. Patches may be confused with macules, but macules are very small and are usually less than 1 centimeter wide. Birthmarks, vitiligo, and hemophilia are all examples of patches.
Patches on the skin are usually the same texture as the surrounding skin and are typically flat. However, patches are sometimes rougher than the surrounding skin, depending on their cause.
Common conditions that cause patches include:
- eczema (a chronic skin condition that causes scaly, itchy patches, sometimes caused by allergies)
- vitiligo (a skin condition that causes white patches)
- psoriasis (an autoimmune disease where the immune system attacks skin cells)
- liver spots (dark patches associated with aging and sun exposure)
- skin moles
Some conditions of the skin can cause dry patches to form. This may result in raised, inflamed areas of skin with a rough texture.
Rashes and hives, often caused by allergies, can also cause patches to appear on the skin.
Make sure to report any unexplained bruising on your skin, or patches that itch or leak fluid to your doctor. Seek medical attention immediately if you develop patches after coming into contact with a known allergen (such as dairy, tree nuts, or peanuts). A severe allergic reaction often starts as a patch or two, but can quickly develop into a medical emergency.
Symptoms of a severe allergic reaction include:
- difficulty breathing
- facial swelling
- swelling around the eyes
- swelling in the throat or mouth
- rapid breathing
- weak pulse
Seek medical attention immediately if you experience any of the symptoms. Untreated severe allergic reactions can lead to anaphylactic shock. This condition can be deadly.
Your doctor may be able to diagnose what caused your skin patches upon physical examination. However, this is not always possible. In some cases, you will be referred to a skin specialist called a dermatologist. A dermatologist will examine the skin, note any symptoms you have been experiencing, take down your medical history, and may take a sample of the patch to determine its cause.
Some allergic reactions are not emergencies. You may be referred to an allergist if you develop raised, itchy patches after eating a specific food or after coming into contact with a known allergen. An allergist will perform an allergen test to determine if the patches are caused by an allergic reaction and what items might be causing it.
Either your doctor or dermatologist can take a biopsy of your patches to help make a diagnosis if they cannot determine a cause just by examination. A biopsy involves taking a sample of the tissue and sending it to a lab to be tested.
In some cases, the cause of your patches cannot be determined by a biopsy or a skin sample alone. In this case, a blood test may be needed to determine the cause. A blood sample can show evidence of infection, autoimmune disorders, or blood disorders.
Your doctor will discuss treatment options with you once they have determined what is causing your skin patches.
If the patches are raised, inflamed, and itchy as in a mild allergic reaction, your doctor may suggest using over-the-counter anti-itch medication such as cortisone cream. This medication can work to relieve the itching and reduce inflammation. You will also be warned to stay away from the allergen that caused your reaction in order to prevent future problems.
Your doctor may give you a medication to carry with you to prevent life-threatening symptoms from occurring when coming into contact with the allergen in the future. This is usually given in the form of an injection of epinephrine with an EpiPen.
If the patches are due to extremely dry skin, using over-the-counter products formulated for eczema or psoriasis may help. In some cases, these medications are not strong enough, so your doctor will prescribe an oral medication to treat it or a prescription-strength cream like pimecrolimus (Elidel) or calcipotriene (Dovonex).
You may be given an antifungal cream to treat the infection if the patches are due to a fungal infection such as ringworm. An over-the-counter antifungal cream often works well to treat ringworm and related causes.
Patches caused by vitiligo may be treatable in the early stages of the condition. Treatment options include:
- corticosteroid cream
- corticosteroid ointment
- immunosuppressant cream
- skin grafts
These patches can be covered using body makeup. Use sunscreen when going outside to avoid sunburn on the vitiligo patches.
Patches due to blood disorders or other medical conditions will be treated according to the condition. This may include a mixture of both topical and oral medications.
Some patches have unknown causes. Your doctor will help you manage the symptoms of these patches.